The invention is more particularly but not exclusively concerned with intercranial pressure sensor assemblies.
Intercranial pressure sensor assemblies conventionally comprise an electrical pressure sensor or transducer connected by an electrical cable to an electrical coupling. The coupling is of a conventional kind and is connected, in use, to a mating coupling, which is in turn connected to an electrical cable extending to electrical monitoring apparatus that records or displays the pressure value. The assembly is installed in the patient in the following way. A hole is drilled through the bone of the skull and two spaced incisions are made with a scalpel, or similar instrument, to form a tunnel through the skin and subcutaneous tissue on the scalp close to the hole. The nose of a pair of forceps is pushed into one incision so that it extends along the tunnel and emerges through the second incision. The nose of the forceps is opened, the sensor is inserted between them and the forceps are closed to grip the sensor tightly. Next, the forceps are pulled rearwardly back through the tunnel and out of the first incision, taking the sensor with them. The sensor is then pushed through the hole into the head so that it lies between the dura and the skull bone, with the pressure-sensitive side of the sensor facing inwards. The sensor is thereby located in the skull, with its cable extending out of the second incision.
The problem with this technique is that the pressure sensor is relatively delicate and is often damaged by the forceps. This can lead to failure or to erroneous readings of pressure.